"We had to safely remove him from his little carrying container, which if you've ever seen the talons on these guys, is a feat in itself," Dr Gelis told 702 ABC Sydney Mornings host Linda Mottram today.

"People think a chick is a little bird, but he was 2.4kg. In a bird that is a very large bird."

The sea eagle was given a gas anesthetic and x-rays were taken before the surgery to remove the hook and line.

It was held overnight for observation, before being returned to its home.

"The surgery went really well and he recovered very well. He's a healthy chick," Dr Gelis said.

Ranger Judy Harrington said yesterday one of the adult sea eagles may have accidentally brought the fishing line to the nest with some food.

"The adults would have brought in food," she told Linda Mottram on Monday.

"The main food that they eat here is the various kinds of fish from the Parramatta River.

"So they have obviously either taken a fish that had line or was discarded along the edge of the river."

She urged people to clean up all their fishing line, hooks and bait after fishing, as many birds accidentally eat the rubbish with dire results.